0728695c63
Some combinations of FAT12 file system parameters could cause a kernel panic due to an unmapped access if the size of the FAT was larger than the CPU page size. The reason is that FAT12 uses 3 bytes to store 2 FAT pointers, leading to partial FAT pointers at the end of buffers of a size that is not a multiple of 3. With a typical page size of 4 KB, this caused the FAT entry at byte offsets 4095 and 4096 to cross the page boundary, with only the first page mapped. This was fixed by adjusting the mapping to always cover both bytes of each FAT entry. Testing revealed 2 other inconsistencies that are fixed by this commit: 1) The calculation of the size of the data area did not take into account the fact that the first two data block numbers are reserved and that the data area starts with block 2. This could cause a FAT12 file system created with the maximum supported number of blocks to be incorrectly identified as FAT16. 2) The root directory does not take up space in the data area of a FAT12 or FAT16 file system, since it is placed into a reserved area outside of that data area. This commits makes stat() report the logical size of the root directory, but with 0 blocks allocated from the data area. PR: 270587 Reviewed by: mckusick Differential Revision: https://reviews.freebsd.org/D39386 |
||
|---|---|---|
| .. | ||
| amd64 | ||
| arm | ||
| arm64 | ||
| bsm | ||
| cam | ||
| cddl | ||
| compat | ||
| conf | ||
| contrib | ||
| crypto | ||
| ddb | ||
| dev | ||
| dts | ||
| fs | ||
| gdb | ||
| geom | ||
| gnu | ||
| i386 | ||
| isa | ||
| kern | ||
| kgssapi | ||
| libkern | ||
| modules | ||
| net | ||
| net80211 | ||
| netgraph | ||
| netinet | ||
| netinet6 | ||
| netipsec | ||
| netlink | ||
| netpfil | ||
| netsmb | ||
| nfs | ||
| nfsclient | ||
| nfsserver | ||
| nlm | ||
| ofed | ||
| opencrypto | ||
| powerpc | ||
| riscv | ||
| rpc | ||
| security | ||
| sys | ||
| teken | ||
| tests | ||
| tools | ||
| ufs | ||
| vm | ||
| x86 | ||
| xdr | ||
| xen | ||
| Makefile | ||
| README.md | ||
FreeBSD Kernel Source:
This directory contains the source files and build glue that make up the FreeBSD kernel and its modules, including both original and contributed software.
Kernel configuration files are located in the conf/ subdirectory of each
architecture. GENERIC is the configuration used in release builds. NOTES
contains documentation of all possible entries. LINT is a compile-only
configuration used to maximize build coverage and detect regressions.
Source Roadmap:
| Directory | Description |
|---|---|
| amd64 | AMD64 (64-bit x86) architecture support |
| arm | 32-bit ARM architecture support |
| arm64 | 64-bit ARM (AArch64) architecture support |
| cam | Common Access Method storage subsystem - cam(4) and ctl(4) |
| cddl | CDDL-licensed optional sources such as DTrace |
| conf | kernel build glue |
| compat | Linux compatibility layer, FreeBSD 32-bit compatibility |
| contrib | 3rd-party imported software such as OpenZFS |
| crypto | crypto drivers |
| ddb | interactive kernel debugger - ddb(4) |
| fs | most filesystems, excluding UFS, NFS, and ZFS |
| dev | device drivers and other arch independent code |
| gdb | kernel remote GDB stub - gdb(4) |
| geom | GEOM framework - geom(4) |
| i386 | i386 (32-bit x86) architecture support |
| kern | main part of the kernel |
| libkern | libc-like and other support functions for kernel use |
| modules | kernel module infrastructure |
| net | core networking code |
| net80211 | wireless networking (IEEE 802.11) - net80211(4) |
| netgraph | graph-based networking subsystem - netgraph(4) |
| netinet | IPv4 protocol implementation - inet(4) |
| netinet6 | IPv6 protocol implementation - inet6(4) |
| netipsec | IPsec protocol implementation - ipsec(4) |
| netpfil | packet filters - ipfw(4), pf(4), and ipfilter(4) |
| opencrypto | OpenCrypto framework - crypto(7) |
| powerpc | PowerPC/POWER (32 and 64-bit) architecture support |
| riscv | 64-bit RISC-V architecture support |
| security | security facilities - audit(4) and mac(4) |
| sys | kernel headers |
| tests | kernel unit tests |
| ufs | Unix File System - ffs(7) |
| vm | virtual memory system |
| x86 | code shared by AMD64 and i386 architectures |